碳纳米管对水中4-氯酚和2,4-二氯酚的吸附性能研究

Adsorption Effects of P-chlorophenol and 2,4-dichlorophenol in Water by Carbon Nanotubes

碳纳米管是一种具有独特结构和优异性能的新型纳米材料。文章利用碳纳米管对水溶液中的4-氯酚和2,4-二氯酚进行了吸附研究,考察了吸附时间、pH值、温度等对吸附效果的影响,并采用Langmuir和Freundlich方程进行拟合,探讨了其可能的吸附机理。研究结果表明,碳纳米管对4-氯酚和2,4-二氯酚的最佳吸附酸度在pH=2～6。碳纳米管对2,4-二氯酚吸附量大于对4-氯酚的吸附量,二者动力学特征均符合准二级动力学方程。研究了4-氯酚和2,4-二氯酚在碳纳米管上的吸附等温线。研究结果表明:4-氯酚和2,4-二氯酚在碳纳米管上的吸附量随着温度的升高而下降。吸附过程是一个放热的过程,Langmuir和Freundlich等温吸附方程均能较好地拟合吸附等温线。碳纳米管能较好地用于除去水溶液中的4-氯酚和2,4-二氯酚。

Carbon nanotube as a new kind of nanomateriat has a unique structure and excellent properties. The adsorption of p-chlorophenol and 2, 4-dichlorophenol from aqueous solution onto carbon nanotubes was studied. The effect of adsorption time, pH and temperature on the adsorption efficiency was investigated. Experimental results were fit with Langmuir and Freundlich equations. Mechanism of adsorption was discussed. Results showed that the adsorption of p-chlorophenol and 2, 4-dichlorophenol onto carbon nanotubes had a maximum at pH 2-6. Adsorption of 2, 4-dichlorophenol onto carbon nanotubes was more than adsorption of p-chlorophenol,both of which fit with pseudo-second order rate equation. The adsorption isotherms of p-chlorophenol and 2, 4-dichlorophenol onto carbon nanotubes were studied. Results indicated that the adsorption of p-chlorophenol and 2, 4-dichlorophenol on carbon nanotubes decreased with the increase in temperature. The adsorptions were exothermic process and all the isothermal data fit well to Langmuir and Freundlich equations. Carbon nanotubes can be used to remove p-chlorophenol and 2, 4-dichlorophenol from aqueous solution.